Ignition controlling device foe



Oct. 6, 1942. M. H. ELKIN 2,297,676

IGNITION CONTROLLING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed Sept. 11, 1940 XX I l X x Z 4 II I INVENTOR.

ATTORNEY.

Patented Oct. 6, 1942 IGNITION CONTROLLING DEVICE FOR COMBUSTION ENGINES Manuern. Elkin, Elmira Heights, N. Y., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application September 11, 1940, Serial No. 356,321

4 Claims. (c1. 14-472) tion Serial Number 344,928, filed July 11, 1940.

It is an object of the present invention to provide a' novel ignition controlling device which is reliable and efficient in operation while being simple and economical in construction.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing which illustrates semi-diagrammatically a power plant embodying a preferred form of the present invention;

In the drawing there is indicated in dotted lines at I an internal combustion engine of conventional form provided with a clutch housing 2 and a variable speed transmission 3 actuated by the engine. Automatic means for shifting the variable speed transmission 3 is provided in the form of a shifter 4 having-a shift rail 5 adapted to engage a shift arm 6, longitudinal movement of which controls the speed ratio of the gears in the transmission 3. The shifter 4 is operated in any preferred manner as by means of fluid pressure from the engine and is controlled by any suitable device responsive to speed of the car in which the power plant is located, the load onthe transmission, or any other desired function or combination of functions of the vehicle. Since the transmission and its automatic control form no part of the present invention, further description thereof is deemed unnecessary.

The engine I is provided with an ignition system-comprising a battery 1 which is connected by an ignition switch 8 to the primary of an ignition coil 9, the opposite terminal ll of which is grounded in the usual manner through a at l9. Switch I5 is provided with a bridging contact 2| normally out of engagementwith contacts I4 and I5 mounted on a sliding plunger 22 normally resting in anotch 23in the shiftrail 5. A second notch 24 is provided in the rail 5 corresponding to the shifted position of the rail, and it will'be 'understoodthat there are as many notches inthe rail as'there are operative positions of the variable speedtransmission.

' The resistor I8 is of that type which whencold has a comparatively low resistance, butwhen heated has a high resistance. Ordinary incane descent lamp filaments have to a greater or less extent such characteristics, so that it is merely necessary to choose a lamp having a filament whose resistance when cold is low enough to effectually ground the ignition system and render it inoperative, while its resistance when hot is such as to cut down the current flowing therethrough to an amount so small as not to adversely affect the operation of the ignition system. Various types of ballast tubes also possess the desired characteristics, and by the selection of a suitable lamp or tube, it has been found readily possible to obtain the desired operatlon of the device while varying the time required to heat the filament and therefore the time during which the ignition is inoperative, to suit the requirements of various types of transmission.

In operation, starting with the parts in the positions illustrated, with the engine in operation the ignition circuit functions in the usual manner since the grounding circuit is opened at the grounding switch l5. When the transmission 3 is to be shifted, the shift rail 5 moves to the right to engage the shift arm 6, and during the initial movement of the shift rail, the switch I5 is closed thereby, thus completing the grounding circuit through the lamp l8, the filament of which is cold and accordingly forms a low resistance connection to the ground. If shifting takes place as usual in a fraction of a second,'the

shift rail moves to line up the notch 24 with the breaker mechanism l2 operated by the engine.

The shifting of the transmission 3 is facilitated by removing the engine load from the transmission during the instant of shifting. As here shown, this is accomplished by providing a grounding circuit comprising a lead l3 connected to the terminal ll of the ignition coil and to a contact l4 of a grounding switch indicated generally by numeral l5. Switch l5 comprises a second contact l5 connected by a lead I! through a thermally sensitive resistor ill to the ground plunger 22 of the grounding switch l5, whereupon the grounding switch is opened and the operation of the engine is restored. If for any reason, the shifting operation is interrupted at an intermediate point, the ground switch l5 will be maintained closed by the shift rail 5. In such case, however, the current flowing from the ignition circuit through the grounding circuit heats the filament of the resistor l8 whereby its resistance rises to such a value that the operative condition of the'engine ignition is restored in spite of the fact that the grounding switch I! remains closed. The engine, therefore, continues to operate until proper measures are taken to secure proper operation of the automatic shifting means. When this is done, switch I! opens since the shift rail has then moved to one of its operative positions and the resistor II immediately cools oil and is ready for the next cycle of operation.

Although but one form the invention has been shown and described in detail, it will be understood that other forms are possible and various changes may be made in the design and arrangement of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is: a

1. In combination with an internal combustion engine having an ignition: system, a grounding circuit for the ignition system including a switch and a resistor in the form oi a metallic filament in an inert atmosphere, and means for closing the switch, the resistance of the filament when and means for closing said switch during the shifting of the transmission, the resistance of the resistor when cold being so low as to render the engine ignition inoperative, and the resistance when heated by the current passing. therethrough from the ignition circuit being so high as to prevent the grounding circuit from adversely aflecting the operation of the ignition circuit.

3. In combination with an internal combustion engine having an ignition system, a variable speed transmission driven thereby, and means for automatically shifting the transmission, a

grounding circuit for the engine ignition inciuding-a normally open switch and an incandescent lamp, the resistance of the lamp when cold being so low as to render the engineignition inoperative, and the resistance 01' the lamp when lit being of such value that the ignition is rendered operative irrespective of closure of the grounding switch.

4. In combination with an internal combustion engine having an ignition system, a variable speed transmission driven thereby, and means for automatically shifting the transmission, a grounding circuit for the engine ignition including 9. normally open switch and an incandescent lamp, the resistance of the lamp when cold being so low as to render the engine ignition inoperative,

MANUELRELKIN. 

